feat(service): sort diagnostics by severity in descending order

crates/biome_service/src/workspace/scanner.rs

@@ -13,6 +13,7 @@ use biome_diagnostics::{Diagnostic as _, Error, Severity};
 use biome_fs::{BiomePath, PathInterner, TraversalContext, TraversalScope};
 use camino::Utf8Path;
 use crossbeam::channel::{Receiver, Sender, unbounded};
+use std::cmp::Reverse;
 use std::collections::BTreeSet;
 use std::panic::catch_unwind;
 use std::sync::RwLock;
@@ -191,6 +192,9 @@ impl DiagnosticsCollector {
             }
         }
 
+        // Sort diagnostics by severity to put the most severe diagnostics first.
+        diagnostics.sort_by_key(|d| Reverse(d.severity()));
+
         diagnostics
     }
 }
@@ -281,3 +285,7 @@ fn open_file(ctx: &ScanContext, path: &BiomePath) {
         }
     }
 }
+
+#[cfg(test)]
+#[path = "scanner.tests.rs"]
+mod tests;

crates/biome_service/src/workspace/scanner.tests.rs

@@ -0,0 +1,47 @@
+use biome_diagnostics::Diagnostic;
+use biome_diagnostics::diagnostic::Severity;
+use biome_diagnostics::serde::Diagnostic as SerdeDiagnostic;
+use crossbeam::channel::unbounded;
+
+use super::*;
+
+#[derive(Debug, Diagnostic)]
+#[diagnostic(
+    category = "lint/style/noShoutyConstants",
+    tags(FIXABLE),
+    message = "Test diagnostic message"
+)]
+struct TestDiagnostic {
+    #[severity]
+    severity: Severity,
+}
+
+#[test]
+fn test_diagnostics_collector_sorting() {
+    let collector = DiagnosticsCollector::new();
+    let (sender, receiver) = unbounded();
+
+    // Send diagnostics with different severities
+    let warning = SerdeDiagnostic::new(TestDiagnostic {
+        severity: Severity::Warning,
+    });
+    let error = SerdeDiagnostic::new(TestDiagnostic {
+        severity: Severity::Error,
+    });
+    let info = SerdeDiagnostic::new(TestDiagnostic {
+        severity: Severity::Information,
+    });
+
+    // Send in an order different from severity
+    sender.send(info).unwrap();
+    sender.send(warning).unwrap();
+    sender.send(error).unwrap();
+    drop(sender);
+
+    let result = collector.run(receiver);
+
+    // Verify diagnostics are sorted by severity (error > warning > info)
+    assert_eq!(result[0].severity(), Severity::Error);
+    assert_eq!(result[1].severity(), Severity::Warning);
+    assert_eq!(result[2].severity(), Severity::Information);
+}